USER20.DOC		R.Gaspari	    12-04-87
	
	This is a replacement lower bios (USER.ASM) for Northstar Advantage.
It embeds SMT no-slot clock call support along with pop-up clock display in
the bios.  See NOSLT20.LBR for more info on SMT clock use for cpm.

	It replaces USER15 which handled function keys from inside bios.  
Since the function key capability was removed, an alternative function key 
handler is provided as YKEY.  This function key handler is not a general 
purpose tool like either Qwikkey or Eric Gan's GKEY.  In fact, if either 
of their source code was available I would never have bothered to write it.  
YKEY is designed as an overlay to any specific program, thus loading with it 
from the command line.  It requires use of DDT for the overlay and requires
special tailoring for every application program for which it is to be overlaid.  
Examples for its use are provided.  See YKEY for details.

	The TIME routine within USER20 is accessed via the reader (RDR:)
jump at boot+15h.  This is not much of an imposition since both PUN:
and RDR: were removed to make room in bios.   As mentioned in USER15, 
I have never in 6 years used the RDR: or PUN: options built into the 
cp/m system via the PIP and STAT commands.

	The POP-UP routine is accessed by a hot-key.  The released version
is initialized for CMND-F1 and CMND-F2.  The function key CMND-F1 gives
one single display of the clock.  CMND-F2 gives continuous display, which 
is toggled on and off by successive CMND-F2.   The reason for the "one-shot" 
display option is that an application program might have useful information 
at the display location (upper right hand corner of the crt screen).  The 
display is quick and short.  There's not much room in bios for exotic options, 
and so the pop-up code was compressed as much as possible.

	For permanent installation into the bios, use SYSGEN and DDT.  
For the Northstar Advantage floppy based system (& Northnet system) use 
an offset of  3E00h.
         a) SYSGEN   to get the image of the OS into RAM at location 1400h
         b) DDT      (original DDT only) to load USER.HEX
            -IUSER.HEX     place USER.HEX in the name buffer
            -R3E00         read it in with an offset of 3E00
            -^C            exit DDT
         c) SYSGEN   to process the modified system image that
                         was created above and store it onto disk.

	For temporary installation, it can be loaded into the bios at
run time along with an application program.  I often use this approach
in case the coldboot disk wasn't re-sysgened with the new USER20 overlay.
Examples of this usage can be found in YK-EXAMP, examples for YKEY.

    Additional general information on patching the BIOS area of Northstar
Advantage systems can be found in section 8.6 of the Northstar Graphics 
CPM Preface.  Send bug reports or comments to R.Gaspari,  6656 W 87th Pl,
Los Angeles 90045.